cmake-modules-webos-native: Simplify the recipe

:Release Notes:
Remove unnecessary duplication from webos_cmake.

:Detailed Notes:

:Testing Performed:
Only build tested.

:QA Notes:
No change to image.

:Issues Addressed:
[ANG-329] Ongoing metadata improvement/cleanup work

Open-webOS-DCO-1.0-Signed-off-by: Martin Jansa <martin.jansa@lge.com>
Change-Id: I2caa947a3dc293fbd624f93b60f387d4b71d4c6e
Reviewed-on: https://g2g.palm.com/4410
Reviewed-by: DCO Verification
Reviewed-by: Martin Jansa <Martin.Jansa@lge.com>
Tested-by: Martin Jansa <Martin.Jansa@lge.com>
Reviewed-by: Susan Montooth <susan.montooth@lge.com>